The present application relates generally to power systems and, more particularly, to a plasma generation device assembly, an arc mitigation device, and a method of assembling the plasma generation device assembly.
Known electric power circuits and switchgear generally have conductors that are separated by insulation, such as air, or gas or solid dielectrics. However, if the conductors are positioned too closely together, or if a voltage between the conductors exceeds the insulative properties of the insulation between the conductors, an arc can occur. The insulation between the conductors can become ionized, which makes the insulation conductive and enables arc formation. In addition, arcs may occur as a result of degradation of the insulation due to age, damage to the insulation from rodents, and/or improper maintenance procedures.
An arc flash causes a rapid release of energy due to a fault between phase conductors, between a phase conductor and a neutral conductor, or between a phase conductor and a ground point. Arc flash temperatures can reach or exceed 20,000° C., which can vaporize the conductors and adjacent equipment panels. In addition, an arc flash or fault is associated with a release of a significant amount of energy in the form of heat, intense light, pressure waves, and/or sound waves, which can cause severe damage to the conductors and adjacent equipment.
In general, the fault current and the energy associated with an arc flash event are lower than a fault current and energy associated with a short circuit fault. Due to an inherent delay between closure of a relay and a circuit breaker clearing an arc fault, a significant amount of damage may occur at the location of the fault.
At least some known systems use an arc mitigation system to divert arc energy from the location of the arc flash or fault. The arc mitigation system includes an arc containment device which often includes a plasma generation device that emits ablative plasma towards electrodes within the arc containment device or live terminals terminating inside the containment device when the arc flash event is detected. The ablative plasma reduces or breaks a dielectric strength of the medium, or insulation, between the electrodes, and the medium breaks down such that an electrical arc is formed between the electrodes. The electrical arc diverts energy from the arc flash location until the source of the energy is abated or disconnected.
At least some known plasma generation devices are formed from alternating layers of ablative material and electrodes, or thin conductive material. The layers of ablative material are typically cut from sheets of the ablative material. Known plasma generation devices are assembled manually which requires additional time, skill, and quality of workmanship. The ablative layers and the electrode layers are glued or otherwise bonded together to form the plasma generation device. Polymerized ablative layers may not bond to electrodes with sufficient strength, which may cause cracking and/or debonding between the layers. In addition, during operation of the plasma generation device, the glue may crack or degrade which leads to voltage creep from a high voltage terminal to other terminals proximate to the high voltage terminal along a surface of an ablative layer. In addition, the cutting of the ablative layers may cause the layers to have a non-uniform surface or edge, thus inhibiting a generation of ablative plasma during operation of the plasma generation device.
Furthermore, manual assembly of the plasma generation devices may cause non-uniform clearance between electrodes or conductive paths of the plasma generation device and/or misalignment between the electrodes and a surface that the plasma generation device is coupled to. In addition, the manual assembly process may result in a large number of plasma generation devices failing to meet specifications due to mismatches between electrodes of the plasma generation device, for example. Such mismatches may cause the plasma generation devices to generate insufficient plasma to enable a short circuit to be formed between phases of the arc mitigation device electrodes. A mismatch of the plasma generation device electrodes may cause a contact region between an electrode and a stud or other coupling member that couples the plasma generation device to a surface to become welded together due to a high current source used with the plasma generation device. In addition, electrodes of the plasma generation device may become dislocated as a result of manually positioning the electrodes between ablative sheets. Dislocation of the plasma generation device electrodes blocks a slit area of the electrodes and may block or undesirably scatter the ejection of plasma from the plasma generating device. An uneven application of bonding material to the plasma generation device electrodes may also insulate and/or block the generation of plasma by the plasma generation device.